Disclaimer:

The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Oncorhynchus clarkii x mykiss are found here.

* HUCs are not listed for states where the observation(s) cannot be approximated to a HUC (e.g. state centroids or Canadian provinces).

Means of Introduction: Intentionally stocked as sport fish.

Status: Maintained by stocking either the hybrid or a parent species where the other parent species naturally occurs (usually stocking the rainbow in cutthroat native range).

Impact of Introduction: Native cutthroat are being replaced by introduced rainbow trout through hybridization and competition. Where the two species naturally co-occur, they rarely hybridize (Sigler and Miller 1963; Behnke, personal communication). Seiler and Keeley (2009) showed that cutthroat trout had reduced growth rates in the presence of cutthroat-rainbow hybrids in laboratory experiments.

Remarks: Recorded from the Southwest as early as 1918 (Sigler and Miller 1963). Private hatcheries sell hybrids between rainbows and Snake River cutthroats (Behnke, personal communication). These two species do not hybridize in areas where both are native (Sigler and Miller 1963). Hybrid trout have not been stocked in Oklahoma (Pigg, personal communication).

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.

Disclaimer:

The data represented on this site vary in accuracy, scale, completeness, extent of coverage and origin. It is the user's responsibility to use these data consistent with their intended purpose and within stated limitations. We highly recommend reviewing metadata files prior to interpreting these data.

Contact us if you are using data from this site for a publication to make sure the data are being used appropriately and for potential co-authorship if warranted. For queries involving fish, please contact Pam Fuller. For queries involving invertebrates, contact Amy Benson.